Keith Thurman first tried to rattle Floyd Mayweather’s cage in 2012. There was little risk to it. Mayweather was in jail at the time.

Thurman had just made his HBO debut. He called out Paulie Maglinaggi, Tim Bradley and, yes, Mayweather. He was 18-0 at the time with 17 knockouts. Maglinaggi sneered, but Thurman was talking past him.

“I threw a dart out there,” Thurman said a couple of weeks ago in Las Vegas. “I was hoping Floyd would want to brush off the dust and take on this loudmouth young puncher. I said, just come see me one time. He’s the King. But every King has his day.”

And Thurman, 26, is now 25-0 with 21 knockouts. He kicked off the Premier Boxing Champions series with an impressive win over Robert Guerrero. He is the WBA welterweight champ and will meet Luis Collazo in another PBC matchup Saturday in Tampa, this time on ESPN.

Does Mayweather really want to fight somebody like this?

Probably not. So Thurman needs not to need Mayweather. He is working on it.

He is outspoken, likable and a bomb-dropper, exactly the kind of American star that boxing should be cultivating. Whether he gets that stage under the stewardship of Al Haymon, and against Haymon fighters, is a separate issue.

“They call Mayweather unbeatable,” Thurman said. “He’s not unhurtable. You can see things he does in the ring. He leans forward, gets on his toes, pulls back and then hits people with the right. I don’t know why people don’t look for it. I would throw a slow jab and trade right hands. Mine’s faster and if it lands first, I’m not getting knocked out, so let’s do it again.

“I saw Mayweather duck down against (Marcos) Maidana to his right, and when that happens he’s vulnerable to a half-left hook, half-uppercut. Not many people have gone to his body, at least not with my power and intensity.”

Thurman wants to transcend the “boxer or puncher” question. He is fond of saying he has enough training to go “100 years deep” in the sport.

He grew up watching Bruce Lee and Stephen Seagall tapes with his dad, who was a martial artist. When he was 7, at his YMCA program in Clearwater, Fla., he watched a school custodian named Ben Getty lead grade-school kids through a boxing exhibition.

“The smallest kid was up there throwing three-punch combos, stepping to the side, throwing them again,” he said. “I was instantly impressed.”

He would learn that Getty had another career before the mop and broom, that he had trained boxers at Fort Bragg after his Vietnam duty, that he had worked with Kelcie Banks and Kenny Gould and even Sugar Ray Leonard. Getty retired in Florida and took a job to keep up. In doing so he would discover another champ.

The YMCA kids formed a boxing program, sometimes making a circle to form a human ring. They became Clearwater Boxing, and the city bought a heavy bag and a real ring.

When Thurman was 13 he scored his first knockout, “over a grown man. Ben said, ‘Looks like you like knocking people out, boy.’ The next day I got my second.’’

Thurman went on to win national tournaments. He also learned more about Getty. What he thought were “fairy tales” were true stories, confirmed in black-and-white photos.

“If he were here today you’d know within two minutes he was a special breed,” Thurman said.

But Getty is not here today. Plagued with complications from Agent Orange and from diabetes, he passed away on his couch, his dog nearby. That happened in 2009, when Getty was only 63. That day Thurman walked across the street to the park, where he began boxing, “just to communicate with his soul.”

By then Dan Birmingham, who had taken Winky Wright and Jeff Lacy to championships, had taken in some of Getty’s fighters at the St.Pete Boxing Gym. Birmingham was Thurman’s mitt man, and now is his trainer.

“We’ve talked a lot about fighting Mayweather,” Birmingham said. “Keith is a lot more creative about getting in there than most people. The key is approach, attack and escape. He has the power and intelligence to pull that off, but nobody knows if he’ll get that chance.”

What’s clear is that Mayweather would have trouble getting inside Thurman’s head. There is too much in there already.